Aeroelastic testing of aerospace vehicles - Experiences gained during four decades

Raja, S and Rajappa, S and Janardhanam, S (2009) Aeroelastic testing of aerospace vehicles - Experiences gained during four decades. In: National Conference on Wind Tunnel Testing (2009-IT11), 12-14 Mar 2009, IISc., Bangalore.

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Abstract

Aerospace vehicles are constructed as light weight, thin walled structures, in order to facilitate more pay loads with improved flight performance. Further, the complex aerodynamic shape requirements bring additional problems to structural designers and analysts to qualiy the thin-walled structures; for example wings, fails and slender bodies like fuselage, launch vehicles must be examined such that they will not develop any aeroelastic instabilities within the specified flight regime. Aeroelasticiy is a science that deals wih an interaction between elastic, inertial and aerodynamic forces. Simulation of aeroelastic system involves coupled structural dynamics and aerodynamics, where analytical models are normally employed. Aerodynamic theories to build such analytical models of lifting surfaces and bodies are well established both in subsonic and supersonic regimes; however there is still not much confidence level achieved in the transonic regime to qualify any aerospace vehicle only through theoretical analysis procedures. Therefore, it becomes appropriate to use the experimental approach to evaluate the transonic aeroelastic characteristics of aerospace vehicles. In the last four decades, Aeroelasticity Group of Structural Technologies Division, NAL has carried out a number of aeroelastic testing projects and contributed immensely to the national aerospace programmes; to name a few LCA, SARAS, SLV, ASLV, PSLVand GSLV. Different kinds of aeroelastic problems have been addressed; both stabilty (flutter, divergence) and response (buffet) solutions are obtained experimentally. Indeed, during the last four decades, the model design and aeroelastic testing methodologies have been evolved to a matured state. Aeroelastic Testing (AET) has the following modules: 13; x2022; Deriving appropriate aeroelastic scale factors13; x2022; Design methodology (Equivalent or Replica)13; x2022; Simulation of boundary effect through model support system13; x2022; Fabrication of components and assembly procedures13; x2022; Non-structural mass simulation13; x2022; Instrumentation on the model and calibration of the sensors13; x2022; Qualification studies for both strength and stiffness13; x2022; Qualification studies for checking the dynamic simulation13; x2022; Wind tunnel testing13; x2022; Data analysis and results interpretation for the full scale vehicle13; AET plays an important role in understanding the aeroelastic behavior of any aerospace vehicle, which either operates at transonic regime or cross over it. This paper brings out our experiences that have been gained in the last four decades of testing the flight vehicles in 1.2m NAL trisonic wind tunnel

Item Type: Conference or Workshop Item (Paper)
Uncontrolled Keywords: 1.2m NAL trisonic wind tunnel;Aeroelastic testing (AET); Aerospace vehicles
Subjects: AERONAUTICS > Aerodynamics
Division/Department: Structures Division, Structures Division, Structures Division
Depositing User: Ms. Alphones Mary
Date Deposited: 25 Aug 2009
Last Modified: 24 May 2010 09:56
URI: http://nal-ir.nal.res.in/id/eprint/5170

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